Time control means for periodic operating apparatus



y 1952 D. w. RIDDELL 2,604,574

TIME CONTROL MEANS FOR PERIODIC OPERATING APPARATUS Filed Jan. 16, 1948 ,RAM PAUSE TIMER.

FORWARD RELAY.

RAM RETURN TIME RELAY co NTACTORS L TRANFORMER.

HEATlNG 21 FURNACE- ,RSQ

I D Q IGJ. GV 1% n i w [1AM i0 502 P 3 TIME OF COMPLETE CYCLE 3), 7..

RAM BACK- FORWARD RAM wAvrs'm' FORWARD END CLOSED RAM wnn'sm' REAR GATE 37; RAM PAUSE TIMER T| TIME RELAY we,

-TR3 DE-ENERGIZED 39 END OF TR} 3i TIMER PERIOD TIME RELAY TR). 1

, I. END OF R1 -'1 J EHO OF TRI 7 PERODQ TR). DEENERG1"LED TIME PERlOD P162. By Donald W. [lidclall A TTORNE Y Patented July 22, 1952 TIME CONTROL MEANS FOR PERIODIC OPERATING APPARATUS Donald W. Riddell, Detroit, Mich assignor, by mesne assignments, to The Ohio Crankshaft Company, Cleveland, Ohio, a corporation of Ohio Application January 16, 1948, Serial No. 2,677

3 Claims. IV This invention relates to induction-heating apparatus and, more particularly, to time control, means for periodic operating mechanism of such apparatus and has for an object the provision of improvements in this art.

One of the particular objects of the invention isto provide time control means in inductionheating apparatus which causes a supervisory action when a matched means fails to perform a given action within a predetermined time.

Another object is to provide time control means in ninduction-heating-- apparatus which causes a supervisory action when a matched consecutively acting means fails to perform a given action within a predetermined time.

Another object is to provide time control means which causes a supervisory action when a similar means fails to begin each of a'plurality of different actions within predetermined times.

; Another object is to provide time control means which causes a first means to perform a given action different from its normal action when a second and related means fails to perform its normalaction within its normal time.

The invention will be described in connection with a reciprocatory pusher and escapement which feed a line of workpieces through a heating furnace and in which the heating means for the furnace is cut off in case the pusher fails to begin a succeeding stroke within a predetermined time from the beginning of a preceding stroke.

The invention will be illustrated inthe accompanying drawings, wherein Figure 1 is a schematic and wiring diagramiof apparatus embodying the invention; and

Figure 2 is atiming chart.

In the drawings, an induction heating furnace coil l providesa through passage for a line of workpieces or billets W which are moved forward at. intervals bya reciprocating pusher or ram and are fed down to theguide .II in front, of the pusher, while the pusher is in its rearward position by escapement means from-an inclined supply chute I3., The escapement means comprises a clamp C and a gate G, controlled respectively by-a clamp valve CV and a gate valve GV, which valves are-actuated in timed relationship with the pusher by a cam l4 carried by a cam bar l5 operated by the pusher.

SwitchesW-l, W--2 are opened when a billet is fed down from-the last position in the chute and are closed whenanother billet drops down into the last position. At the forward end of its stroke theram-closes a switch RS--l and opens a=switch..RS-Z,.whichrswitches reverse as the 2 ram starts back; A solenoid $02, when energized, operates theram valve RV-and causes the ram to moveback and when deenergized allowsthe ram to move forward.

The control means comprises an electrical system which includes a start push buttonPl having normally open switches Pl| Pl--2, a istop push button P2 having a normally closed switch P2I, a start pilot relay RI having three normally openswitches R.r| R i-2- and RIM-.3; a ram pilot relay R2 having two normally. open switches R2-i and R2-2, a heat pilot relay R3 having two normally openswitches R3l and R32, a time-delay relay TR2 for forward ram movement, a time-delay relayTR3 for rearward ram movement, and a timer 'Tlfor interposing a pause in the ram. movements.

The time-delay relay TR2 includes a normally open instantaneous switch- T-R2-2 and anormally closed time-delay opening switch TR2 I. The time-delay relay TR3includes :a normally closed switch TR33 and a normally open switch TR3--2 and a normally closed time-delay opening switch TR3.--l. Thetimer Tl has a synchronous motor T-M- which opemtescontinuously after the apparatus is started, being energized through switch R'l3 of relay RI whichis locked in throughv its switchRL-l after .once being energized. v

The; timer motor actuates a gear train-which in turn sets upa pulse? motion.

T|-l and-Tl-2 ,are switch elementspLa double polev double throw. switch. .Tl-l jis...only closed momentarily (approximately 2 seconds) out ;of the complete. cycle time. When: TL-r-l closes-and if. the ram is in thenforward-pos'ition,

it will energize. the ram pilot. relay R2 whichin turn will bring the ram back.

. Switch 'I'l--2 is placed inthe circuitlonlyito keep the timer motor energized after the start pilot relay switch Rl.-2 hasbeenopened and onlyguntil thetimerassumes startingpositio' (that is when Tl---I is closed). I

,Tl-2-- opens when T.l-.-I-c1os es, thus openin the L2 circuit to the timer motor. I

When the rampilot relay or theramsolenold valves are deenergized, the ram assumestheforward position (normal), this .intu-rn closes'switch RS--l, the timer alsoassumes its starting position closing switch TI-L With this condition, it allows the ram 'to'be called back immediately after the start button is pushed-and the heater will go into production without anydelay.

When the switch R3:-| of heat pilot relay R3; is closed, it causes the induction heating poll I8 to be energized. This may be done in a number of ways and for illustration, a relay R is shown, having a normally open switch RG-I which, when closed, causes an appropriate circuit and contactors represented by I9 to cperate to apply heating current in the coil I8. A transformer and capacitor 2I are shown in the high frequency heating circuit.

The main lines LI, L2 are provided with a switch S-I and a pilot lamp 22.

To prepare for the start of operations, the main line switch SI of LI, L2 is closed to energize power buses 30, 3I respectively. This lights pilot lamp 22 to show that the control system is energized.

For the purpose of describing the operation of the apparatus, it will be assumed that workpieces W are in the chute I3 preparatory to being dropped into position for pushing into the heating coil. Thus, with a workpiece W in position, the normally open switches W--I, W2 are closed. Closure of the switch WZ completes a circuit from the power line bus I3I to the now closed switches W2, the wire I43, the energization coil of the ram forward relay TR-2 to the power bus I39. This closes switch TRZ-Z and starts delayed opening switch TR2-I to open. It will be assumed that the time period has expired and this switch is now open. It will also be assumed that the ram is in the forward or left position, thus closing R.SI and opening RS2.

To start operations, the start push button PI is pressed to momentarily close normally open switches PI-I and PI--2.

Closure of switch PII completes a circuit from the bus I3I through the normally close. switch P2 I, wire I32, the now closed normally 'open switch PII, wire I33 through the energization coil of the start pilot relay RI to the bus I30, thus energizing RI. Energization of relay RI closes its normally open switches RI--I RI2 and RI3. Closure of switch RII completes a holding circuit for relay RI from the 'wire I32 to the wire I33.

no eifect as yet because the circuit is open elsewhere. It also closes RI3 energizing the ram pause timer TI to L7,, the circuit being from the wire I 3|, the normally open now closed switch RI-3, wire I34, and the motor M to the wire I30. Energization of the motor M immediately opens normally closed switch TI2 and closes normally open switch TII. TII remains closed long enough to initiate the following steps and then reopens.

Closure of TII completes a circuit from wire I34, the energization of which was previously traced, through the now closed switch TiI, wire I35, the now closed switch RS-I, the wire I36, the now closed switch W--I, the wire I3? and through the energization coil of the ram pilot relay R2 to the bus I30.

Energization of the ram pilot relay R2 closes it normally open switches R2I and 132-2. Closure of switch R22 completes a circuit from the wire I33, the energization of which was previously traced through the now closed switch R22, the wire I38 and through the now closed switch W-I to the wire I31 to complete a holding circuit for the ram pilot relay R2, which circuit will not be broken unless the switch W-I opens as a result of a billet being dropped to the ram level. Closure of switch R2I completes the circuit from the bus I3I to the wire I4I through the energization coil' or the solenoid S02 to the wire L--i. Energization of rain valve solenoid S02 operates valve RV and supplies fluid to the rod end of the ram cylinder and the ram returns, that is, its piston moves rearwardly or to the left to the head end of the cylinder.

Energization of the wire I35 by closure of switch TII of the pause timer also serves to energize time delay relay TR3 thus preparing the normally-closed, delayed-opening switch TR3-I to start at the same time that the ram starts back so that, in effect, the timer TBS races the ram on its return and up to a time when it is supposed to complete some action, for example, to start forward again after a billet has been fed down. At this stage, energization of TR3 has no effect.

When the ram starts to return, it opens RS-I and closes RS2. Closure of RS2 serves to bypass the timer switch TII, holding TR3 energized and tending to open the time delay switch TRZ-I, which remains closed, however, unless the ram fails to function and return forward in a predetermined time.

As the'ram approaches the rear end of its stroke, its cam I4 causes clamp valve CV to be actuated to clamp a billet in the next to last position in the chute. At the rear end of its stroke, it opens the gate to feed down a billet upon the guide support I2.

When a billet drops out of last position upon the guide, it opens switches W-I and W2. Opening of W-I deenergizes R2, opening switches R2I and R22. Opening of switch R2-I deenergizes the ram valve solenoid S02 to allow the valve RV to operate and cause the ram to move forward.

It should here be noted that when the control system is energized by closing SI, and assuming that a billet is in the last or feed-down position to keep W2 closed, the time-delay relay TRZ will at once be energized and will be kept energized as long as W2 is kept closed, the circuit being from the wire I3I through the now closed switch W-E, the wire I43, the energization coil of the relay TRZ to the wire I30. Opening of W2 deenergizes TR2 and causes it to open its switch TR22 and to close TR2-I, both without delay.

As the ram moves forward, its cam first causes the gate to close the bottom end of the chute and later causes the clamp to release its billet and allow that and the whole stack of billets to descend. The lowermost billet in descending again closes switches WI and W2. Closure of WI has no immediate eilect but closure of W-2 energizes 'IRZ again.

Energization of TR2 closes its switch TRZ -Z at once and begins a new timing period for time delay opening switch TR2-I to open. It is here set to open after the ram has moved forward and paused at the end of the forward stroke for its preset waiting period.

At the end of its forward stroke, the ram closes RSI and. opens RS-Z. Opening of RS2 deenergizees wire I35 and TRB and this closes TR3I and TR3--3 and opens TR32, all without delay. 7

Closure of TR33 (TR22 and TR2-I being closed) energizes the heat pilot relay R3, the

- circuit-being -tracedfrom the: wire: I 3 I normally 'closed switch" TR2-I, the wire I 48, now I closed -switch TR2-2, the wire- I 44, 'nowclosed: switch TR3'--3, -the wire I 45,-closed normally openswitch RI+2, the"wireI46, theenergization coil of J R3 to the bus I 33 to close its switches R3-I- and and through TR2-2 and TR2-I. Closure of R3I-energizes the contactor relay R4 to close R4I and through .contactors I9 and the related high frequency current system to supply heatmingcurrent to the heating "coil I0.

At the end of the waiting period, the-timer TI energizesram pilot'relay' R2 to -cause the ram It may also be here noted that in order for the heat pilot relay R3 to be energized, it is necessary that either one of the normally closed time delay opening switches TR.2I or 'I'R3-I must be closed even though the particular relay coil is energized. Energization of TR3 closes TR3--2 and leaves TR3--I closed (until later opened) so heat pilot relay R3 is held in when TR2-I shortly opens. This circuit may be traced from the wire I3I, the closed switch TR3-I, the wire I42, the now closed switch TR3-2, the wire I44, the now closed switches TR3-3, the wire I45, the closed normally open switch RI2 and through the energization coil R3 to the wire I30. If TR2-I opens first, R3 will be deenergized to open R3-I so that the later closure of TR32 will be ineffective to keep the heat on. However, closure of push button switch Pl-Z would restore the heating current.

Similarly, if TR3I opens (as it should shortly after the gate closes) before TR2-3 closes when the gate closes, R3 will be deenergized and closure of TR22 (TR3 still being energized and TR3-3 open) will not energize R3. PI2 would apply heat. This permits the operator to put billets in the chute and start the machine again without waiting.

The timing of operations will be clearer from consideration of Fig. 2, showing the cycle diagram. The duration of one complete cycle is represented by the top horizontal line 30 which extends between the vertical start line 3I and the finish line 32. The second horizontal line 33 represents the ram movements. It starts back at line 3I and completes its backstroke at a vertical line 34. It starts again at the vertical line 35 and completes its forward stroke at the vertical line 36. The ram Waits at the forward end of its stroke, as represented by the distance between the lines 36 and 32. The third horizontal line 31 represents the gate operation, which opens approximately at the line 34 to feed down a billet, and closes approximately at the line 35.

The short horizontal line 42 represents the period of time in which the switch TII is closed, closing of which switch initiates the beginning of a new complete cycle.

The horizontal line 38 represents the action of time-delay relay TR3. It is energized at ordinate 3| and deenergized at the line 36 but its time-delay switch TR3-I is set for actuation at a point 2I5a which is a short time after the ram is supposed to start forward. Hence, if there is any jam in the ram return or the billet Again, closure of -feed, the-heating current will be. cut'ofi. Ifthere is no' billet in-the feed-down position: to close switches W--'I", 'W.2, the ram :also will, stop when it-reaches the front end of its stroke,-as-

-suming thatthe ram did not jam-on its-backstrokebut merely failed to get back on'time.

' The line 39 represents the action of timeedelay relay TR2. It is energized at the ordinate-1'35 where the ram starts forwardand remains energized until the ram returns; Its sWitch'TR2-I,

however, is timed f'or actuation at the point 3Ia which is slightly after the ram is scheduled 'to start its 'returnmovement. Hence, if there is any jam in the forward movement of the ram or if--theproper-pause at the frontend of the ram-stroke-has not been observed, the heating currentis cut off.

- To -make the original-setting of the time-re- =-l-ays'- -TR2 or TR3, itis only necessary tea-place the movable'contact element of-the-relay at a point some distance'beyond' the point required.

by-the operations to bematched and supervised and then gradually to move the contact back until only a slight margin of safety is left. In this way the supervisory response may be made as fine or coarse as may be desired.

It will thus be seen that the invention provides a very useful means for supervising the timed operations of parts having one or more periods of proper operation, and that the supervisory means will act to control when and only when the periodic operating means fails to func tion within a predetermined period.

While the invention is illustrated in connection with an exemplary embodiment, it is to be understood that the uses of the invention are very wide and are not to be limited except by the prior art and the scope of the subjoined claims.

What is claimed is:

1. Induction-heating apparatus comprising, in combination, an induction-heating coil having a heating chamber into which a plurality of metallic workpieces are adapted to be moved; a source of power for said coil; switch means for controlling the application of power to said coil; reciprocatory mechanism for moving workpieces into said coil, the cycle of movement of said mechanism being divisible into a reciprocatorymovement portion and delay portion intermediate the reciprocating movement portions and each portion having a determinable time period; t1mer means for initiating a complete cycle of reciprocation; a supervisory timer means associated with at least one portion of each cycle, said supervisory timer means having a preset t me period in excess of said last mentioned portion acting to actuate said switches and deenerglze said coil if the said portion of said cycle exceeds said preset time period on said supervisory timer.

2. Induction-heating apparatus comprising an nduction-heating coil having a heating chamber into which a plurality of metallic workpieces are adapted to be moved; a source of power for said coil, switch means for controlling the application of power to said coil; reciprocatory mechanism for moving workpieces into said coil, the cycle of movement of said mechanism being divisible 1nto a reciprocatory-movement portion and delay portion intermediate the reciprocating movement portions and each portion having a determinable time period; timer means for controlling the time period of the complete cycle of reciprocation and a supervisory timer associated with at least one of said portions having a preset time period greater than the normal time period of that portion, said supervisory timer being op, eratively associated with said switch means controlling the application of power to said coil for cutting oil the source of power in the event the time of said portion equals or exceeds the preset time period.

3. Induction-heating apparatus comprising, in combination, an induction-heating coil having a heating chamber into which a plurality of metallic workpieces are adapted to be moved; a source of power for said coil; switch means for contro1 ling the application of power to said coil; reciprocatory mechanism for moving workpieces into said coil, the cycle of movement of said mecha nism being divisible into a reciprocatory-movement portion and delay portion intermediate the reciprocating movement portions and each portion having a determinable time period; timer means for controlling the length of a complete cycle of reciprocation; a pair of supervisory timers each associated with difierent of said portions and having a preset time period in excess of the determined time of said portion, said timer being operatively associated with said mechanism and said switch to deenergize said coil in the event the time period for one of said portions is greater than the preset supervisory timer period.

DONALD W. RIDDELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,442,311 Watson Jan. 16, 1923 1,878,888 Rambush Sept. 20, 1932 2,325,638 Strickland Aug. 3, 1943 2,408,350 Strickland Sept. 24, 1946 2,465,306 Durand Mar. 22, 1949 

